1. Field of the Invention
The invention relates generally to a lifting assembly for precast concrete insulated building panels having a reduced thermal conductivity. In another aspect, the invention relates to a thermally conductive lifting assembly coupled with a pair of parallel precast concrete slabs separated by a layer of insulation, which can be partially disconnected to eliminate thermal conductivity between the concrete slabs.
2. Description of the Related Art
It is known to utilize concrete building elements, such as wall panels and roof panels, that are pre-cast prior to shipment and installation on a construction project. Frequently, such panels are insulated, with a layer of insulation interposed between two parallel concrete slabs. A building panel can be very heavy and must be removed from a mold, placed on a transporting vehicle, and installed at the construction site as a single piece using cranes, helicopters, and other heavy equipment.
To facilitate the attachment of hooks, cables, chains, and the like for moving such panels, the insulated building panels are fabricated with metallic lifting anchors integrated into the concrete slabs during molding of the slabs. When the concrete has cured, the lifting anchors are partly embedded in the concrete slabs and partly exposed for connecting hooks, cables, chains, and other lifting and moving apparatus.
Known metal lifting devices set into the concrete slabs can be a single element that spans the insulation layer and creates a thermal bridge between the slabs across which heat energy can be transferred. This typically can reduce the insulation rating of the building panel. However, use of such lifting devices is necessary.
A need exists for a lifting assembly, and a method of constructing and using such a lifting assembly, for precast concrete insulated building panels that does not transfer heat energy from one concrete slab to the other.